A coupled discrete-continuum approach to simulate moisture effects on damage processes in porous materials

In the present paper, a coupled model for the prediction of damage under hygro-mechanical loading is developed. The model combines a mechanical and a moisture transport model within a poromechanical framework. Damage is incorporated by embedded displacement discontinuities, allowing an accurate prediction of the crack path within a coarse finite element mesh. To simulate the preferential wetting around a crack, a discrete front tracking method to predict the fluid transport through cracks is incorporated in a continuous moisture transport model. The computational features and capabilities of the coupled model and the effects of moisture on dimensional stability, crack opening evolution and cracking behaviour are illustrated with different examples of combined mechanical and moisture loading during three point bending tests on a fictitious sandstone.